1. Technical Field
Embodiment of the present invention relate to an optical sensor unit that detects density of an image formed on an image carrier and a position of an end portion of the image, and an image forming apparatus incorporating the optical sensor unit.
2. Related Art
Known image forming apparatuses form image density detection patterns and/or image displacement detection patterns on an image carrier to read these patterns by an optical sensor unit for correcting a density and a write timing of an image.
Some of these image forming apparatuses include a cleaning mechanism that removes flying foreign materials and/or residual toner remaining on optical parts such as a light source and a light receiving element of the optical sensor unit.
For example, Japanese Patent No. JP-4312547-B (JP-2005-070676-A) discloses a shutter that prevents adhesion of toner scattered to a detection surface of an image density detector that can detect density detection patterns formed on the surface of an intermediate transfer belt and a compression spring that links movement of the shutter with movement of a recording medium transfer unit.